1. Field of the Invention
The present invention relates to an improved splice for fluoropolymer coated webs or meshes. More particularly, the present invention relates to an improved splice for fluoropolymer coated glass mesh fabrics.
2. Description of the Prior Art
Endless belts have been utilized in various industrial applications, for example, in drying and heating applications in the food and paper industries. Endless belts formed from a fiber glass mesh fabric coated with a polymeric material have increasingly been utilized in such applications, replacing the conventional metallic endless belts. Different polymeric material coated glass fabrics can be fabricated to fit particular needs of each application. Of these, fluoropolymer, especially polytetrafluoroethylene (PTFE), coated glass fabrics are particularly suited for specialty applications and provide many desirable characteristics that were lacking from the conventional metallic or other polymeric material coated endless belts. Such desirable characteristics include chemical resistance, thermal resistance, flexibility and microwavability.
Conventionally, an endless belt made from a fluoropolymer coated glass fabric is formed by overlapping and stitching or heat-sealing the two ends of the belt fabric. Various metallic lacing devices, such as alligator lacing and clipper lacing, as they are known in the art, have also been utilized to make endless belts.
However, the conventional methods of joining the ends of a fluoropolymer coated glass fabric to form an endless belt have not been satisfactory. The joined end produced from the conventional stitching or heat-sealing methods is not only labor intensive but also has a substantially thicker dimension and is significantly rigid. Furthermore, the stitching and/or heat-sealing procedures result in blockage of the voids of the mesh unless particular care is taken during the stitching process. As for the metallic lacing methods, the metallic lace introduces inflexibility into the joined end that has different physical and chemical characteristics than the rest of the belt. In addition, the metallic lace renders the resulting endless belt to be unsuitable for microwave applications.
Many other methods of forming an endless belt have been disclosed, for example, in U.S. Pat. Nos. 3,936,3.38; 4,130,679; and 2,391,731. Particularly, U.S. Pat. No 3,936,338 teaches a method of joining and bonding the ends of a PTFE coated fiber glass belt by applying an overlapping strip of a thermoplastic film over the joined ends of the belt under heat and pressure. Although the splicing method disclosed therein may be less labor intensive than the other prior art methods, the thick joined ends and blocked voids of the mesh at the joined ends may not be suitable for certain applications.
In addition, as is known in the art, it is a common practice in the industry to repair damaged segments or an endless belt, instead of replacing the entire belt, for obvious economical reasons. However, the prior art splicing methods are not suited for such repairing applications since they are labor intensive procedures that introduce thick inflexible joined sections to the belt.
It would therefore be desirable to provide a splice that can be easily formed and is not subjected to the above-mentioned disadvantageous characteristics.
It would further be desirable to have a splicing method that is not only suited to fabricate endless belts but also can be utilized to repair damaged segments of the belts.